the nature and variety of living organisms Flashcards
what characteristics do living organisms share?
- M: they move
- R: they respire
- S: they respond to their Surroundings
- G: they grow and develop
- R: they reproduce
- E: they excrete their waste
- N: they require nutrition
- C: they control their internal conditions
describe the common features shown by plants (eukaryotic organism)
- multicellular
- cells contain chloroplasts, able to do photosynthesis
- cellulose cell walls
- store carbs as starch or sucrose
examples of plants?
flowering plants, such as a cereal (e.g. maize) and a herbaceous legume (e.g. peas/beans)
describe the common features shown by animals (eukaryotic organisms)
- multicellular
- no chloroplasts in cells, not able to do photosynthesis
- no cell walls
- usually have nervous co-ordination & able to move from one place to another
- often store carbs as glycogen
examples of animals
mammals (e.g. humans) and insects (e.g. housefly and mosquito)
describe common features shown by fungi (eukaryotic organism)
- not able to do photosynthesis
- body usually organised into a mycelium made from thread-like structures called hyphae, which contain many nuclei
- some examples single-celled
- cell walls made of chitin
- feed by saprotrophic nutrition
- may store carbs as glycogen
definition of saprotrophic nutrition?
feeding by extracellular secretion of digestive enzymes onto food material & absorption of the organic products
examples of fungi
mucor has typical fungal hyphae structure, and yeast (single celled)
describe common features shown by protoctists (eukaryotic organisms)
- microscopic single celled organisms
- some have features like an animal cell (like amoeba, which live in pond water)
- others have chloroplasts & more like plants (like chlorella)
- pathogenic example: plasmodium, causes malaria
examples of protoctists
- amoeba: live in pond water, features like animal cell
- chlorella: chloroplasts, more like plants
- plasmodium: pathogenic, causes malaria
describe the common features shown by prokaryotic organisms such as bacteria
bacteria:
- microscopic single celled organisms
- have cell wall, cell membrane, cytoplasm, plasmids
- lack nucleus but contain circular chromosome of dna
- some can do photosynthesis but most feed off dead/living organisms
examples of bacteria
- lactobacillus bulgaricus: rod-shaped bacterium used in production of yoghurt from milk
- pneomococcus: spherical bacterium that acts as pathogen causing pneumonia
what are eukaryotes?
organisms whose cells contain a proper nucleus - a membrane sphere containing linear chromosomes of DNA. they all also have other organelles with outer membranes, e.g. mitochondria
what’s a prokaryote
organisms that don’t have a proper nucleus, instead the genetic material is in the cytoplasm in the form of a single circular chromosome
what are pathogens?
microorganisms which cause infectious disease, they harm the host by releasing toxins or damaging cells.
all viruses are pathogens, and bacteria, fungi, & protoctists can also be pathogens.
